The invention relates to a cooling system which is suitable for cooling electronic structural units or assemblies. The cooling system is provided with a housing and, therein, with at least one cooling channel having an inflow and an outflow and intended for a coolant, the electronic structural unit resting over a large area against a heat-conducting cooler wall of the housing.
As is known, the power dissipation and hence the heat evolution of the electronic assemblies are increasing disproportionately with the power-related further development of the electronic structural elements. It is true that these components are becoming smaller and smaller, but their efficiency and hence the heat to be removed are increasing. Furthermore, owing to their compactness, these electronic elements are positioned in a smaller space so that once again a higher local heat evolution results. The power dissipations achieved would be realizable only with complicated and bulky cooling bodies in the case of fan cooling and are therefore unacceptable. In the case of large losses, air cooling therefore clearly reaches its limits.
The new high-performance processors deliver about 70 to 100 W over an area of about 10 cm2 and thus achieve a far higher heat flux density. The processor manufacturers predict that a further increase in the waste heat is to be expected in the years ahead. In view of this development, those skilled in the art are considering liquid cooling for such applications. Liquid cooling more effectively withdraws the heat from the electronic assemblies, with the result that a higher power density is possible. The liquid cooling systems permit more compact switch cabinets with numerous electronic components. The liquid coolers moreover operate quietly and do not tend to give rise to dust or to accumulate particles from surrounding gases, which can furthermore reduce the cooling power.
A prior cooling apparatus is disclosed (e.g. in US-2008/0066888-A1), in which a pin-block is installed in a cooling channel—transversely to the cooling wall of a semiconductor. These metal pins are therefore arranged so as to be distributed in the liquid channel of the cooler, transversely to the main direction of flow of the coolant, in order to improve the heat transfer between the electronic structural element and the coolant.
Although conventional liquid-cooled cooling bodies have proved to be adequate in the past, they are found to be unsuitable for many of the present-day components with higher and in particular increasing energy consumption.
In the case of another cooling device of this type (US-2005/0143000-A1) [also known as SHOWERPOWER (trademark of Danfoss, Inc.) in practice], three plates arranged a distance apart from one another are provided in a housing, and these plates together form a distributor unit for a coolant for cooling an electronic power component via a cooling plate. The first plate has outlet openings and discharge openings which have a nozzle-like design with the aid of one tubular element each and are connected to a feed channel or discharge channel formed between the adjacent plates. The coolant flows from an inlet through the feed channel, is distributed from there by the openings in the second plate and via the pipelines into the outlet openings of the first plate, penetrates from there to the underside of the cooling plate and flows—with removal of the heat and simultaneous cooling of the power components—through the discharge openings into the discharge channel and from there to the outlet.
In the above arrangement, a distributor apparatus having nozzles is used for transverse transport of the cooling liquid to the metal surface of the semiconductor, with the result that the heat transfer could be increased to a certain extent, but the complicated design of the inlet and outlet nozzles is associated with manufacturing problems. On the other hand, this cooler consists of many elements, and it is for this reason that its assembly or its maintenance requires an unacceptably long time.
It is therefore an object of the present disclosure to provide an improved cooling system of the type mentioned at the outset, which, while being as compact as possible, permits a more effective cooling structure and a lighter, simpler design.
To achieve these goals and others as shall be evident by consideration of this description, accompanying drawings, and appended claims, there are provided systems in which the cooling apparatus has indentations in a cooler wall which are formed transversely or perpendicularly to the cooling channel and are open towards the cooling channel. An insert element having an inner longitudinal channel is inserted into each indentation, an outer longitudinal channel which is connected to the inner longitudinal channel being formed for the coolant between the indentation and the associated insert element. That end of the insert element which engages the cooling channel may be provided with an inclined entry surface and an inlet opening to the inner longitudinal channel. Inclined entry surfaces with the inlet openings of the adjacent insert elements may be arranged offset relative to one another. Instead of the entry surfaces which are inclined per se, it is also possible to provide an inflow channel which connects the entry surfaces and which becomes correspondingly deeper and thus achieves about the same effect as singular inclined entry surfaces on each individual inlet opening. This alternative configuration results in a completely inclined inlet opening along the inflow channel, which inlet opening performs as an inclined inlet surface for each singular entry surface.
Further details and advantages of the invention may also be understood from the description of the Figures.